Light Colored Scalar as Messenger of Up-Quark Flavor Dynamics in Grand Unified Theories

The measured forward-backward asymmetry in the t tbar production at the Tevatron might be explained by the additional exchange of a colored weak singlet scalar. Such state appears in some of the grand unified theories and its interactions with the up-quarks are purely antisymmetric in flavor space. We systematically investigate the resulting impact on charm and top quark physics. The constraints on the relevant Yukawa couplings come from the experimentally measured observables related to D0--D0bar oscillations, as well as di-jet and single top production measurements at the Tevatron. After fully constraining the relevant Yukawa couplings, we predict possible signatures of this model in rare top quark decays. In a class of grand unified models we demonstrate how the obtained information enables to constrain the Yukawa couplings of the up-quarks at very high energy scale.Comment: 13 pages, 11 figures, version as published in PR

The Reaction 7Li(pi+,pi-)7B and its Implications for 7B

The reaction 7Li(pi+,pi-)7B has been measured at incident pion energies of 30-90 MeV. 7Li constitutes the lightest target nucleus, where the pionic charge exchange may proceed as a binary reaction to a discrete final state. Like in the Delta-resonance region the observed cross sections are much smaller than expected from the systematics found for heavier nuclei. In analogy to the neutron halo case of 11Li this cross section suppression is interpreted as evidence for a proton halo in the particle-unstable nucleus 7B.Comment: 4 pages, 4 figure

Standardized Assessment of Concussion in football players

This is the publisher's version, also available electronically from http://www.neurology.org/content/48/3/586.Article abstract-The recent formulation of guidelines for the management of concussion in sports adopted by the American Academy of Neurology specifically calls for the development of a standardized, systematic sideline evaluation for the immediate assessment of concussion in athletes. The present study involved the preliminary investigation of the feasibility and clinical validity of a standardized version of a brief sideline examination complied in accordance with these guidelines. This examination, intended for use by athletic trainers, was administered by three trainers to 141 nonconcussed high school football players at three separate schools. All players suspected of suffering a concussion (N = 6) during the fall 1995 season were also tested immediately following their injury. The examination was easily administered and scored. The concussed players as a group scored significantly below the nonconcussed controls and below their own baseline (pre-injury) performance, despite their all having been considered by the trainers to have suffered mild, grade 1 concussions. Although preliminary, these data suggest that a standardized sideline examination of this type can be useful in detecting concussion and determining fitness to return to play

The impact of epilepsy surgery on sex hormones and the menstrual cycle in female patients

AbstractWe investigated the impact of temporal lobe epilepsy surgery on sex hormones and menstrual cycles. Sixteen female patients with temporal lobe epilepsy were investigated prior to surgery and 3, 6, and 12 months after surgery. The patients received carbamazepine (CBZ) as monotherapy (10 patients ) or in combination with other antiepileptic drugs (six patients ). Antiepileptic drugs were maintained after surgery. During the 1-year follow-up after surgery eight patients (50%) remained completely free of seizures. In another four patients (25%) only rare disabling seizures occurred. There were no significant differences between pre-surgical and post-surgical serum concentrations of testosterone, free testosterone, prolactin, dehydroepiandrosterone sulfate, growth hormone, cortisol and sex hormone binding globulin. There was, however, a significant increase in serum androstenedione concentration 6 months post-surgically (P< 0.02). Documentation of menstrual cycles in addition to laboratory parameters revealed individual post-surgical changes of the menstrual cycle in eight patients . Four patients had a change in menstrual periodicity: two patients with complete seizure control had regular cycles instead of oligomenorrhoea and two patients with incomplete seizure control had oligomenorrhoea instead of regular cycles. These data indicate that at least in some patients with temporal lobe epilepsy surgical treatment influences menstrual periodicity

Measuring kinetic coefficients by molecular dynamics simulation of zone melting

Molecular dynamics simulations are performed to measure the kinetic coefficient at the solid-liquid interface in pure gold. Results are obtained for the (111), (100) and (110) orientations. Both Au(100) and Au(110) are in reasonable agreement with the law proposed for collision-limited growth. For Au(111), stacking fault domains form, as first reported by Burke, Broughton and Gilmer [J. Chem. Phys. {\bf 89}, 1030 (1988)]. The consequence on the kinetics of this interface is dramatic: the measured kinetic coefficient is three times smaller than that predicted by collision-limited growth. Finally, crystallization and melting are found to be always asymmetrical but here again the effect is much more pronounced for the (111) orientation.Comment: 8 pages, 9 figures (for fig. 8 : [email protected]). Accepted for publication in Phys. Rev.

Diffusion and jump-length distribution in liquid and amorphous Cu33_{33}Zr67_{67}

Using molecular dynamics simulation, we calculate the distribution of atomic jum ps in Cu$_{33}$Zr$_{67}$ in the liquid and glassy states. In both states the distribution of jump lengths can be described by a temperature independent exponential of the length and an effective activation energy plus a contribution of elastic displacements at short distances. Upon cooling the contribution of shorter jumps dominates. No indication of an enhanced probability to jump over a nearest neighbor distance was found. We find a smooth transition from flow in the liquid to jumps in the g lass. The correlation factor of the diffusion constant decreases with decreasing temperature, causing a drop of diffusion below the Arrhenius value, despite an apparent Arrhenius law for the jump probability

Sophisticated falsification and research cycles: Consequences for differential character weighting in phylogenetic systematics

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/72703/1/j.1463-6409.1997.tb00424.x.pd